      program demo_isspace
      use M_strings, only : isspace
      implicit none
      integer                    :: i
      character(len=1),parameter :: string(*)=[(char(i),i=0,127)]
         write(*,'(20(g0,1x))')'ISSPACE: ', &
         & iachar(pack( string, isspace(string) ))
      end program demo_isspace
